Conventionally, a system power supply IC which can output multiple power supply voltages is known (see, e.g., Patent Literature 1). The system power supply IC has multiple built-in power supply circuits in a package. With this configuration, the multiple power supply voltages can be output with a lower cost compared with a case where power supply circuits are individually mounted.
In the above-described kind of system power supply IC, usually, an output of a power supply voltage is controlled by a control device, such as a microcomputer which controls the whole system. In other words, in order to output the power supply voltage from the system power supply IC, the control device should be in operation state.
In a configuration of system, an output of the specific power supply voltage is needed to operate a peripheral device. In some cases, in order to restrict power consumption, the operation of the control device itself is not needed. On the other hand, in a usual operation, a control by the control device needs to be prioritized.